Phyllomedusa bicolor is an Amazonian amphibian of the Phyllomedusidae Family, and is found in the forests of Brazil, the Guianas, Venezuela, Colombia, Peru, and Bolivia. It is one of the largest tree frogs of the Amazon. The males measure up to 11.8 cm from snout to vent1 (Figure 1A). Popularly known as “Kambô”, “Kampô,” or “Kampu,” natives use the toxin secreted by the skin of this frog in traditional medicine1,2. The name Kambô is also used to describe the ritual of applying the poisonous secretions of the frog to the skin (Figure 1B). Natives also call the poisonous secretion “toad vaccine”.

Indigenous people of Brazil and Peru remove the white-colored secretion (Figure 1C) that the frog exudes when it is stimulated, and collect it on wooden spreaders for later use. This secretion is rich in bioactive peptides2 that the animal uses as a defense mechanism to kill or induce unpleasant experiences (e.g., discomfort, regurgitation) in predators that attempt to ingest this amphibian. Application of the “toad vaccine” is conducted by superficially burning the surface of the skin with a sharp object (or small piece of vine called ‘titica”), typically the arms of men or legs of women, and making several “points”2. The dried secretion from the spreader is then applied to each of the small burns/points2,3 (Figures 1B and 1D). The symptoms are almost immediate2, resulting in a great deal of discomfort (a strong burning sensation, nausea, stomach pain, and vomiting) for approximately 15 minutes. However, relief can only be achieved by removing the poison from the skin by washing the affected area. Fasting the night before the application and drinking plenty of water is also recommended2.

For centuries indigenous people have used Kambô as a form of medicine to “strengthen the body’s natural defenses,” to ward off “panema” (bad luck), and in rituals to increase hunting success3. With the colonization of the Brazilian state of Acre, rubber tappers adopted this technique, and the ritual is now customary in several regions of Brazil, including in large urban centers3, and has reached North America and Europe2. It has been reported that peptides isolated from the skin secretions of the Phyllomedusaspecies exhibit antimicrobial properties(e.g., against Pseudomonas aeruginosas) and also inhibit protozoa (e.g., Trypanosoma cruzi)4in vitro. This suggests a role for amphibians in the development of new anti-microbial drugs.

Recent reports have revealed the side-effect of Kambô5–9 treatment, including death10. Leban et al.5reported the case of a 44-year-old female in Slovenia who drank six liters of water after applying Kambô,and gradually developed nausea, vomiting, confusion, lethargy, muscle weakness and spasms, fits/convulsions, loss of consciousness, short-term memory, and developed syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Pogorzelska and Łapiński6 treated a 34-year-old male patient in Poland with a chronic history of alcohol and marijuana use, who had signs of transient hepatitis, with Kambô to maintain sobriety. Kumachev et al.7 also reported the case of a 32-year-old female patient who was admitted to a hospital in Canada with prolonged nausea, frequent episodes of vomiting, and abdominal discomfort eight hours after Kambô treatment. Li et al.8 treated a 24-year-old female at a first-aid facility in the United States with symptoms of prolonged vomiting, facial flushing, facial swelling, altered mental status, and restlessness 22 hours after using Kambô. Roy et al.9 also reported the case of a 33-year-old woman in the United States who presented with potential psychosis (with characteristics of paranoia, anxiety, bizarre delusions, labile humor, and panic attacks) associated with Kambô use. The sudden death of a 42-year-old overweight man with signs of coronary disease associated with the use of Kambo was reported in Italy10. These authors suggested that the hypotensive effects of Kambô may have resulted in reduced myocardial perfusion and tachycardia, which led to sudden cardiac arrhythmia. In Pindamonhangaba, in the state of São Paulo (Brazil), the death of a 52-year-old man was reported shortly after the application of the Kambô by a practitioner who obtained the Kambô skin secretions from of the state of Acre11. All of these complications have been reported in regions far from where Kambô is traditionally used (Western Amazon), and applied by practitioners who may not have the same experience as those who traditionally perform the ritual, and thus poses an additional health risk.

In addition to its traditional use, Kambô has spread via urban expansion into alternative therapy clinics and Brazilian Ayahuasca religions (Santo Daime and União do Vegetal) with new practitioners, called holistic and medical therapists3. Natives are concerned that new practitioners may misapply Kambô or use the skin secretions of other species of amphibians (“Sapo-cururu” Rhinella marina)3, resulting in health complications or even death. Many people have reported the benefits of this therapy as if it were a “panacea” that is able to cure many diseases (low immunity, headache, gastritis, diabetes, blood pressure problems, cirrhosis, labyrinthitis, epilepsy, impotence, depression, cancer and AIDS3). These reported benefits may increase the demand for alternative treatments like Kambô; however, evidence of its efficacy is insufficient and studies of its side effects have not been conducted. The National Sanitary Surveillance Agency12 has ordered the suspension of all types of advertising for this alternative therapy, and revealed that there is no scientific evidence to guarantee the quality, safety, and efficacy of this treatment or its indication for any type of disease, imbalance, or treatment of any acute and chronic processes.

Due to the reports of complications and death, it is necessary to caution the public on the contraindications regarding the use of Kambô2, such as severe cardiovascular conditions, hypotensive syndromes, and to limit water intake after the ritual, in order to reduce the risk of contracting SIADH syndrome. In addition, since Kambô is also traditionally used to induce abortions, pregnant women should not participate in this ritual2. Excessive applications (overdose), and treatment of children with a lower body mass, should be avoided as mass-to-dose ratio may be relatively higher during the treatment in these two groups of patients. The secretion of P. bicolor contains several different uncharacterized toxins6. Additional studies on the pharmacological potential of amphibians are necessary, and the risk of bio-piracy should be monitored. Trafficking of these animals and their secretions, and the possible impact on the P. bicolorpopulation in their natural habitats, should be expensively studied.